Three convicts plot to sneak out of prison, steal a fortune in diamonds from a maharajah, and then creep back in to provide themselves with the perfect alibi. However, their seemingly flawless plan is threatened by the arrival of a strict new prison officer. Comedy, starring Peter Sellers, Bernard Cribbins and Lionel Jeffries.

Three criminals plan to break out of prison the day before their release in order to carry out a daring jewel robbery, intending to establish the perfect alibi by returning to jail afterwards. First however they must get out, a task made more difficult by a new, stricter prison officer.